Numerous electronic watches are available which use high stability oscillators as time standards and display time information in a digital fashion. One of the difficulties encountered with many currently available digital watches is the complex routine that must be followed in order to set or change the time indicated on the watch. In some watches, a button for actuating up counters must be used in a particular sequence to cause each of the time registers to be set to the desired value. Other watches use a plurality of buttons, magnetic wands, and other accessory devices to achieve similar results. These various complex measures necessary for the setting of time make it difficult to easily change the time in the watch when crossing time zones or for setting an alarm.
Electronic calculators of various sorts have been available for some time, however, present electronic calculators perform computations only with scalar quantities, that is, values that are not changing with time. While a number of calculators have been provided with displays which are extinguished after a certain period of time in order to conserve power, the calculator circuitry itself usually remains in an operational state thus continuing to consume power at a relatively high level even though no information is being displayed and no calculations are being made.
At least one previous patent, U.S. Pat. No. 3,803,834, has disclosed the combination of an electronic watch and a calculator in a single case. This combination, however, makes no provision for computations using time varying quantities in combination with scalar quantities, nor does it provide for control of the clock portion via the calculator. The calculator and the watch in the aforementioned reference operate entirely separately and only share a common display and keyboard.